Abstract

This work presents an experimental and modeling study of the electromagnetic environment in the vicinity of a high voltage substation located in eastern Algeria (Annaba city) specified with a very high population density. The effects of electromagnetic fields emanating from the coupled multi-lines high voltage power systems (MLHV) on the health of the workers and people living in proximity of substations has been analyzed. Experimental Measurements for the Multi-lines power system proposed have been conducted in the free space under the high voltage lines. Fields intensities were measured using a referenced and calibrated electromagnetic field meter PMM8053B for the levels 0 m, 1 m, 1.5 m and 1.8 m witch present the sensitives parts as organs and major functions (head, heart, pelvis and feet) of the human body. The measurement results were validated by numerical simulation using the finite element method and these results are compared with the limit values of the international standards. We project to set own national standards for exposure to electromagnetic fields, in order to achieve a regional database that will be at the disposal of partners concerned to ensure safety of people and mainly workers inside high voltage electrical substations.

Abstract

Supersonic aircraft produce a sonic boom when flying faster than the speed of sound. In order to rule out detrimental"br" e ects for inhabitants of overflown areas, civil supersonic flights (like the Concorde) were allowed to fly over water only."br" Due to progress in aircraft design, the super sonic boom may be reduced considerably in the future. Such ”Low Sonic"br" Boom”-signatures will be considerably quieter and sound completely di erent compared to conventional sonic booms."br" Currently, the sensation and the subjective response of humans to future ”Low Sonic Boom”-signatures is not known."br" For an assessment of human responses to ”Low Sonic Boom”-signatures, a Sonic-Boom simulator has been built at the"br" University of Oldenburg as a pressure chamber with a volume of about 9 m"sup"3"/sup". Two 18” loudspeaker chassis enable the"br" production of an overpressure of up to 20 Pa for a signature duration of 200 ms. The background noise level in the"br" chamber is very low (21 dB(A)) and the chamber has a very small reverberation time of T"sub"20"/sub"=0.2 s averaged over octave"br" bands from 63 Hz to 8 kHz. A vibration platform is installed in the chamber to simulate whole-body vibration that may"br" occur in connection with ”Low Sonic Boom”-signatures.